1. Field of the Invention
The present invention relates generally to the correction of heat imbalances of a building resulting from the effects of incident solar radiation, and more particularly, this invention relates to a system and method for entrapping the heat component of incident solar radiation and either distributing it to other portions of the building or returning it to the atmosphere.
2. Description of the Prior Art
Wall units, particularly windows, exposed to incident solar radiation are known to present difficulties in the heating and air conditioning of buildings. These difficulties vary with the seasons, with the weather, and with the spatial orientation of the wall unit or window in question. For instance, in both hot and cold weather the heat from incident solar radiation causes imbalances, sometimes quite severe, in the air conditioning and heating of the building, which either requires separate units or separate control of a master unit. Even so, a uniform temperature can not be achieved over the entire gradation of solar energy heating effects on the building without excessive expense.
During the summer, the solar radiation incident on building walls and windows causes a heat gain in the adjacent interior areas, thus increasing the burden on the cooling system of the building. During the winter, the heat gain from such incident solar radiation can relieve some of the burden on the heating system of the building, but on clear days the walls and windows exposed to incident solar radiation allow substantial amounts of excess heat energy to enter the adjacent areas, while other areas in the same building (not adjacent to wall units exposed to incident solar radiation) receive insufficient heat energy. The disproportionate heat gain from this source places undue burdens on the heating, ventilating and air conditioning system of the building, for it requires that such system supply cooling to the former areas at the same time that it supplies heating to the latter areas.
At least one system (that illustrated in U.S. Pat. No. 3,590,913 -- Tschudin) attempts to deal with the ultimate problem of air conditioning the interior areas by constructing wall units of parallel glass panels separated by a cavity through which a light-transmitting heating or cooling medium can be circulated. This system is inordinately expensive and inefficient because: (1) it allows the ambient outside environment to withdraw from (or add to) the heating (or cooling) medium as much or more heat energy than the adjacent indoor environment is able to withdraw (or add); and (2) it fails to utilize the incident energy which otherwise would result in the undesirable heat gain.
Some wall units, particularly windows, are designed with outside surfaces which reflect incident solar radiation to reduce the heat gain in the adjacent interior areas. These wall units are inefficient in that the incident solar radiation is reflected back to the ambient atmosphere and not utilized. This is particularly wasteful in the winter months when the mid-day sun, being low in the sky, causes more than average amounts of incident radiation to strike the vertical walls exposed to the south and west, while at the same time the winter temperatures cause greater than average heat loss from all walls, particularly those exposed to the north and east.
It is possible to avoid this inefficiency by constructing the wall unit or window in such a way that the reflective surface can be removed when conditions dictate that the solar radiation be allowed to enter and add heat to the adjacent interior area. An arrangement described by Nicholas Fuschillo in an article entitled "Semi-Transparent Solar Collection Window System", Solar Energy, Vol. 17, pp. 159-165 (1975), avoids this manual operation by erecting a second, transparent panel outside of the reflective surface and providing valves to allow venting the heat from the area between the panels either to the outside (during hot weather) or to the adjacent interior area (during cold weather). Neither of these types of systems, however, deals with the problems of differential heating of interior areas adjacent to wall units or windows exposed to incident solar radiation and interior areas adjacent to wall units or windows not exposed to incident solar radiation.